Thanks everyone for your help here...
... but I still cant figure out how to do what I'm trying to do... and I think I'm probably missing something very obvious.
What I want, just to clarify, is to have two collections containing the same images. One collection has the images converted to B/W, the other would keep it all in color.
So I've been trying to translate what I'd do in LR to Cap1 but it doesn't work.
I make new variants of everything, put them into a new collection, convert one to b/w, copy and apply the adjustments, and everything in the collection is great.
EXCEPT that the color collection is now also in b/w.... in LR they behave as separate files and I assume that's the idea here.
Is it because I'm putting the images into a separate collection?
Is it because I'm just a bad person?